The overall objective of this research is to determine the role of differential initiation rates on mRNAs in regulating protein synthesis in normal, virus-infected, interferon treated and transformed cells. The significance of the inhibition of the rate of translation elongation in interferon-treated cells will be assessed, especially in regard to its possible selectivity against rapidly initiating (viral) mRNAs. The mechanism by which elongation inhibition is accomplished will also be studied. The intrinsic initiation rates on various viral and host mRNAs will be measured, and the factors which determine intrinsic initiation rate will be identified. Particular attention will be paid to the role of mRNA "cap" structures, and cap-specific initiation factors.